Background

Tea tree oil comes from the leaves of Melaleuca alternifolia. Tea tree oil is thought to have antiseptic properties and has been used to prevent and treat infections.

Other traditional uses of tea tree oil include treatment of fungal infections (including fungal infections of the nails and athlete's foot), dental health, parasites, skin allergic reactions, and vaginal infections. In addition, there is evidence supporting tea tree oil use for acne; however, further research is needed.

Tea tree oil should not be taken by mouth; there are reports of toxicity after consuming tea tree oil by mouth. When applied to the skin, tea tree oil is reported to be mildly irritating and has been associated with the development of an allergic skin reaction, which may limit its potential as an agent for the skin in some people.

Dosing

The below doses are based on scientific research, publications, traditional use, or expert opinion. Many herbs and supplements have not been thoroughly tested, and safety and effectiveness may not be proven. Brands may be made differently, with variable ingredients, even within the same brand. The below doses may not apply to all products. You should read product labels, and discuss doses with a qualified healthcare provider before starting therapy.

Adults (18 years and older)

Due to reports of severe side effects, it is strongly recommended that tea tree oil not be taken by mouth. Although tea tree oil solution has been used as a mouthwash, it should not be swallowed. In addition, there is no proven effective dose of tea tree oil.

For dental plague/gingivitis, 2.5% tea tree oil has been used to brush teeth twice daily for eight weeks.

For acne, 5% tea tree oil as a gel has been applied to the skin once daily for three months or twice daily for 20 minutes, then washed off, for 45 days.

For allergic skin reactions, 25-120 microliters of 20-100% tea tree oil has been applied to the affected areas of the skin.

For dandruff, 5% tea tree oil shampoo has been applied to the scalp for three minutes daily, prior to a rinse, for four weeks.

For eye infections, 50% tea tree oil has been used as a weekly eyelid scrub or tea tree shampoo has been used a daily eyelid scrub for six weeks.

For methicillin-resistant Staphylococcus aureus (MRSA), a 4% tea tree oil nasal ointment and a 5% tea tree oil body wash has been used for an unspecified duration. A 10% tea tree cream has been applied to the nostrils three times daily for five days followed by a 5% tea tree body wash used on the body for a minimum of once daily for five days. A 10% tea tree cream was applied to skin wounds and lesions as an alternative to the body wash. A 3.3% tea tree oil water-mixture has been used during each wound cleaning and dressing change.

For fungal nail infections, 100% tea tree oil has been applied to the affected areas twice daily for six months.

For genital herpes, a 6% tea tree oil gel has been applied to the affected skin five times daily.

For thrush, an alcohol-based or alcohol-free tea tree solution has been used four times daily as a mouthwash for 2-4 weeks. For denture inflammation, one milliliter of tea tree oil has been added to the standard treatment of a five milliliter dose of Coe-Comfort™ tissue conditioner; this mixture has been used by mouth. Daily treatment information is unknown, but it has been used for 12 days.

For athlete's foot, 10% tea tree oil has been applied to the affected area twice daily after washing and drying feet. A 25-50% tea tree oil solution has been applied to the affected area twice daily for up to four weeks.

For vaginal infections, a 20% solution of tea tree oil has been applied by using a tea tree soaked tampon for 24 hours. A dose of 200 milligrams of tea tree oil vaginal pessaries in a vegetable oil base has been used daily for five days.

Children (younger than 18 years)

Due to reports of severe side effects, it is strongly recommended that tea tree oil not be taken by mouth. Although tea tree oil solution has been used as a mouthwash, it should not be swallowed. In addition, there is no proven effective dose of tea tree oil.

For eye infections, eyelid scrubs of 50% tea tree oil or eyelid massages with 5% tea tree ointment have been performed for 4-6 weeks.

For skin infections, a four microliter drop of tea tree oil plus iodine or tea tree oil alone has been used twice daily for up to 30 days or until the lesions healed.

For viral warts, tea tree oil was applied to warts once daily for 12 days.

Evidence

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

Acne

Although available in many products, little information is available from human studies to evaluate the benefit of tea tree oil used on the skin for the treatment of acne. Tea tree oil may reduce the number of inflamed and non-inflamed lesions.

C

Allergic skin reactions

Early small studies show that tea tree oil applied to this skin may reduce histamine-induced inflammation. Further research is needed to confirm these results.

C

Athlete's foot

Early studies report that tea tree oil may have activity against several fungal species. However, at this time there is not enough information to make conclusions for or against the use of tea tree oil on the skin for this condition.

C

Bad breath

Tea tree oil is used in mouthwash for dental and oral health. However, there is currently insufficient evidence in humans to make a conclusion for or against this use of tea tree oil. Tea tree oil can be toxic when taken by mouth and therefore should not be swallowed.

C

Dandruff

Early research reports that the use of 5% tea tree oil shampoo on mild-to-moderate dandruff may be effective and well tolerated. Further research is needed to confirm these results.

C

Dental plaque/gingivitis

Study results on the effects of tea tree oil mouthwash on gum inflammation and plaque are mixed. Further research is needed before a strong conclusion can be drawn.

C

Eye infections

Early studies found that tea tree oil helped rid the eye area of an infection caused by ocular parasitic mites. Large, well-designed clinical trials are needed before a strong conclusion can be made.

C

Fungal nail infection (onychomycosis)

Although tea tree oil is thought to have activity against several fungus species, there is not enough information to make conclusions for or against the use of tea tree oil on the skin for this condition.

C

Genital herpes

Laboratory studies show that tea tree oil has activity against some viruses, and it has been suggested that a tea tree gel may be useful as a treatment on the skin for genital herpes. However, there is currently not enough information to make a conclusion for or against this use of tea tree oil.

C

Hemorrhoids

In early research, a gel with tea tree oil decreased symptoms of hemorrhoids. More studies are needed.

C

Lice

Early studies have found that tea tree alone or in combination with other agents may be effective against lice. However, large, well-designed trials are still needed before a strong conclusion can be made.

C

Methicillin-resistant Staphylococcus aureus (MRSA) infection

Laboratory studies report that tea tree oil has activity against methicillin-resistant Staphylococcus aureus (MRSA). It has been proposed that using tea tree oil ointment in the nose and a tea tree wash on the body may treat colonization by these bacteria. However, there is currently not enough information from human studies to make conclusions for or against this use of tea tree oil.

C

Skin infections (viral)

A study comparing tea tree oil and iodine in treating children with Molluscum contagiosum, a viral skin infection, showed that both tea tree oil alone and iodine alone lacked a significant effect on the number of infected areas; however when iodine and tea tree oil were used together, the amount of skin infected areas significantly decreased. Tea tree oil may be effective for human papilloma virus (HPV) warts as supported by a lower-quality human study. Further studies are required for a conclusion to be reached.

C

Thrush (Candida albicans of the mouth)

In laboratory studies, tea tree oil has been shown to kill fungus and yeast such as Candida albicans. However, there is not enough information available from human studies to make conclusions for or against this use of tea tree oil. Tea tree oil can be toxic when taken by mouth and therefore should not be swallowed.

C

Vaginal infections (yeast and bacteria)

In laboratory studies, tea tree oil has been shown to kill yeast and certain bacteria. However, there is not enough information available from human studies to make conclusions for or against this use of tea tree oil for vaginal infections. Although tea tree oil may reduce itching caused by yeast or bacteria, it may cause itching from dry skin or allergy.

C

Wound healing

Tea tree oil has been studied for its ability to absorb odors and to be used in the dressing of wounds. In lower-quality human studies of non-healing wounds, the addition of tea tree oil to the treatment resulted in the healing of the wound. Further research is needed for conclusions to be reached.

Uses based on tradition or theory

The below uses are based on tradition or scientific theories. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

Interactions

Interactions with Drugs

Tea tree oil may interfere with the way the body processes certain drugs using the liver's "cytochrome P450" enzyme system. As a result, the levels of these drugs may be altered in the blood, and alter the intended effects. People taking any medications should check the package insert and speak with a qualified healthcare professional, including a pharmacist, about possible interactions.

Interactions with Herbs and Dietary Supplements

Tea tree oil may interfere with the way the body processes certain drugs using the liver's "cytochrome P450" enzyme system. As a result, the levels of these drugs may be altered in the blood, and alter the intended effects. People taking any medications should check the package insert and speak with a qualified healthcare professional, including a pharmacist, about possible interactions.

Tea tree oil may also interact with anti-acne herbs and supplements, antibacterials, antifungals, antihistamines, anti-inflammatory herbs and supplements, antivirals, dental herbs and supplements, herbs and supplements for cancer, herbs and supplements for parasite infections, herbs and supplements for the skin, herbs and supplements for worm infections, herbs and supplements that affect the nervous system, herbs and supplements that affect the blood, herbs and supplements that decrease immune function, hormonal herbs and supplements, insect repellants, iodine, and skin drying herbs and supplements.

Methodology

This information is based on a systematic review of scientific literature and was peer-reviewed and edited by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).

Note: Tea tree oil should not be confused with cajeput oil, niauouli oil, kanuka oil, or manuka oil obtained from other Melaleuca species.

Safety

The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.

Allergies

Allergic reactions have been reported with tea tree oil when taken by mouth or used on the skin. Skin reactions ranged from mild contact dermatitis (skin inflammation) to severe blistering rashes.

Avoid in people with a known allergy or sensitivity to tea tree oil (Melaleuca alternifolia), to any of its parts, Balsam of Peru, benzoin, colophony (rosin) tinctures, eucalyptol, or to plants that are members of the myrtle (Myrtaceae) family.

Side Effects and Warnings

Tea tree oil is likely safe when applied to the skin in recommended doses and durations in non-allergic people.

Use cautiously in pregnant and breastfeeding women or those undergoing childbirth, due to reports that tea tree oil decreases contraction strength.

Use cautiously when applied to the skin or when used as an eyelid scrub.

Use cautiously when used in people with linear IgA disease (an immune disease), as tea tree oil may cause a blistering disorder.

Use cautiously when used in combination with lavender oil, as this may cause a widespread rash.

Use cautiously when used as a mouthwash, due to moderate burning of the mouth upon contact as reported in human research.

Use cautiously when used with vancomycin, due to a potential interaction.

Avoid taking by mouth in people of all ages, due to possible nervous system toxicity, skin allergic reactions, decrease in white blood cells, and stomach and intestine complaints.

Avoid in people with a known allergy or sensitivity to tea tree oil (Melaleuca alternifolia), to any of its parts, Balsam of Peru, benzoin, colophony (rosin) tinctures, eucalyptol, or to plants that are members of the myrtle (Myrtaceae) family.

Avoid applying to the skin in boys before puberty, as this could cause reversible gynecomastia (growth of breast tissue) with tea tree oil and lavender oil.

Avoid applying around the breast, because tea tree oil may have mild hormonal activity.

Avoid adding into the middle ear, as toxicity of the ear has occurred with large doses.

Pregnancy and Breastfeeding

Use cautiously in pregnant and breastfeeding women, and during childbirth due to a lack of enough scientific information.

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